Compared with ordinary steel-shell batteries, pouch cells have the advantages of high energy density, small size, light weight and flexible design, and are therefore favored by many users and widely used in mobile portable electronic products. In order to increase the energy density of the battery, the package bag of the pouch cell is also becoming thinner and lighter. The light and thin development of package bags will inevitably affect the safety of pouch cells, and the safety of pouch cells has always been the most important issue. Therefore, the package bag of the battery must be able to meet the requirements for good insulation, corrosion resistance, water resistance, high strength and good molding of the electrode assembly.